This invention relates to the fabrication of crystal plates, and in particular to a method and apparatus for batch testing the crystallographic orientation of the plates.
Crystal plates, such as quartz, are useful in a wide variety of piezoelectric devices such as filters and oscillators. In many of such devices, a precise crystallographic orientation angle for each plate is often a key element in acceptable performance. In accordance with the usual prior art process, the crystallographic orientation of each plate is determined after all lapping and grinding by x-ray analysis making use of the Bragg conditions for reflection. While such techniques are accurate, they require that each plate be checked on an individual basis which, of course, adds considerably to processing time and the cost of fabrication.
It is therefore a primary object of the invention to provide a method and apparatus which will allow batch testing of the crystallographic orientation of crystal plates.